chemia: Fluorescence

Evidence: 100 • authority: 72

Fluorescence is one of two kinds of photoluminescence, the emission of light by a substance that has absorbed light or other electromagnetic radiation. When exposed to ultraviolet radiation, many substances will glow (fluoresce) with colored visible light. The color of the light emitted depends on the chemical composition of the substance. Fluorescent materials generally cease to glow nearly immediately when the radiation source stops. This distinguishes them from the other type of light emission, phosphorescence. Phosphorescent materials continue to emit light for some time after the radiation stops. This difference in duration is a result of quantum spin effects. Fluorescence occurs when…

Evidence: 54 • authority: 92

Fluorescence in Direct Dental Resin-Based Composites and Natural Teeth: A Narrative Review.. Background/Objectives : Human teeth naturally fluoresce due primarily to organic components within dentine, contributing to their vitality and appearance under ultraviolet (UV) light. Contemporary resin composites increasingly incorporate fluorescent agents to reproduce this property and improve aesthetic integration with natural dentition. This narrative review examines the fluorescence characteristics of natural teeth and direct resin composites, evaluates methods used to assess dental fluorescence, and identifies factors influencing fluorescence stability and biomimetic performance. Methods : Pee…

Evidence: 45 • authority: 72

A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with several π bonds. Fluorophores are sometimes used alone, as a tracer in fluids, as a dye for staining of certain structures, as a substrate of enzymes, or as a probe or indicator (when its fluorescence is affected by environmental aspects such as polarity or ions). More generally they are covalently bonded to macromolecules, serving as a markers (or dyes, or tags, or reporters) for affine or bioactive reagents (antibodies, peptides, nucleic acids). Fluoro…

Evidence: 45 • authority: 72

A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, to produce ultraviolet and make a phosphor coating in the lamp glow. Fluorescent lamps convert electrical energy into visible light much more efficiently than incandescent lamps, but are less efficient than most LED lamps. The typical luminous efficacy of fluorescent lamps is 50–100 lumens per watt, several times the efficacy of general lighting incandescent bulbs with comparable light output, which is on the close order of 16 lm/W. Fluorescent lamp fixtures are more costly than incandescent lamps b…

Evidence: 42 • authority: 92

Single-visible-light-modulated photoswitches with aggregation-induced emission for super-resolution imaging.. Super-resolution fluorescence imaging (SRI) overcomes the traditional optical diffraction limit, enabling the visualization of microstructures at the nanoscale. Central to this technique is the precise photo-modulation of molecular fluorescence emission, yet it remains a formidable challenge to develop visible-light-responsive photoswitching systems with aggregation-induced emission (AIE) that are biocompatible and suitable for solid-state applications. Herein, we construct a series of unique fluorescent photoswitches with single-visible-light modulation by incorporating sulfone uni…